1. Field of the Invention
This invention relates generally to movable storage systems, and specifically, to an automatic item locator for such systems.
2. Description of the Related Art
Mobile aisle storage systems include a plurality of storage units. Each storage unit has a plurality of shelves which may be divided into compartments. The units are aligned in a parallel arrangement having opposing faces forming bays on which the shelves are located. Typically, the storage units are mounted on wheel carriages which ride on tracks or rails recessed in the floor. Each storage unit has a motor or driven drive train propelling it bidirectionally on the tracks. Usually, outermost units in the series are stationary and other units are controlled to move toward and away from each other to form aisles between units. The units are spaced to incorporate a single aisle or multiple aisles to maximize the use of available space. The units can also incorporate a secondary aisle and increase the accessibility of the system.
In some systems, movement of the storage units is controlled by switches located at one end of each unit, as shown, for example, in U.S. Pats. Nos. 4,437,711, 4,733,923, 4,743,078, and 4,759,592 all to Dahnert, U.S. Pat. No. 4,119,376 to Moyer, and U.S. Pat. No. 4,783,618 to Artrip. The controls can be integrated so that pressing one button near a selected aisle to be accessed will move all of the storage units necessary to open the selected aisle.
The bays, shelves, and compartments are generally labelled to uniquely identify different locations. In addition, the items stored in the units, such as paper files, may be labelled for identification. Typically, an operator who desires to retrieve a file will determine its location from an index or other record. The operator will then go to the aisle where the file is stored and, if the aisle is closed, press the button which moves the units to open the aisle. Safety devices are provided to ensure that an aisle occupied by a person or object is not closed. The operator finds the file location and removes the file.
It would be desirable to have an automated system which eliminates the need to determine the location of a selected item prior to entering the storage area. The system should automatically permit access to the storage location of the selected item and should provide a visible indication near the storage location. The system should also be able to track the status of items which are stored in or removed from the storage units.